I read this on a Mac java mailing list:
...Then there is the Javax USB project (JSR-080), which will eventually be a standard -- but again, there is currently no OS X support.
Just a quick follow-up to my own message, in the event anyone comes around here looking for something similar.
I've been in contact with a team of engineers over at Sun, along with some other Open Source developers, and it looks like an imminent effort is going to be made to implement javax.usb using the libusb project. As libusb is available for Mac OS X, this bodes very well for having full USB device access for Java-based applications in the near future.
Could this be a great way to write some JInput plugins?